The present invention relates to an electrochemical method of trapping ions in a silicon oxide film or a silicon oxy-nitride film, which is used for producing solar cells and integrated circuits.
Conventional methods of trapping ions in oxide films or nitride films include electron beam evaporation methods (see to, for example, J. Chem. Soc Chem Commun., 1983, 1407-1408 and J Electrochem. Soc., 134 (1987), 72-76), resistance heating evaporation method, sputtering evaporation methods, and the like.
However, the above-described conventional methods have problems, ie that, since ions are trapped by evaporation, a large evaporation apparatus is required and several hours are required for sample change, evacuation and evaporation